Found the problem. The line mod.loggerMemoryRangeFxn = $externFxn(cn + '_writeMemoryRange__E');

should have been mod.loggerMemoryRangeFxn = $externModFxn(cn + '_writeMemoryRange__E');

From Sasha:When you are assigning a function to a parameter, that function could be declared in a module or it could be a non-RTSC function. In the first case, you use $externModFxn to signal to the config that the function is already declared and that it doesn't have to be declared again in the big C file. In the second case, the declaration in the big C file is required and you should use $externFxn.

The whole point of that is type checking. The type of the config parameter and the function assigned to it must match.